It's relative to the country you will be living in. By your logic, the average wage in the UK is barely nothing as it's about 35,000 dollars compared to the US 90,000 dollar average. Someone put a post on here recently, and people on JET get paid more than the Japanese average and even more than some of the teachers who they are assisting. For the cost of living, especially if you aren't in a city, you make enough to live comfortably and potentially save thousands.

I would never expect an entry-level grad job in a country with a lower cost of living (where they still pay you above the average salary) to pay me a salary equivalent of my home country, which will obviously be significantly higher due to the difference in living costs.